JPH08227824A - Capacitor - Google Patents

Abstract

PURPOSE: To enhance safety and reliability and to make the life long by loading a capacitor element comprising metallized films, which are a metal evaporation electrode divided to serve as a safety mechanism, into an encapsulating container, provided with a safety device, and positively operating the safety mechanism. CONSTITUTION: One side of a polyethylene terephthalate film 1 is provided with decomposed metal evaporation electrodes 2 to serve as a safety mechanism. Then, polypropylene films are overlapped and wound, and the thermal spraying of metal is performed on both surfaces of a capacitor element. After heating aging, a lead wire is attached. Then, the capacitor element is loaded into an encapsulating container, wherein a bellows-type safety device is provided. Polybutene oil is used and impregnated, and the capacitor is formed. Thus, the capacitor, which has the secure safety mechanism, high safety, high reliability and long life, is realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capacitor for electric equipment.

[0002]

2. Description of the Related Art As shown in FIG. 2, a conventionally known split electrode is a metallized film 3 having a metal vapor deposition electrode 2 formed on an insulating film 1 and a narrow fuse portion 4 formed on the metallized film 3. 2 is divided into a plurality. The divided electrodes are a security mechanism having a security function, and are in the form of a set of microcapacitors in which the ends of the wound metallized film 3 are connected by a sprayed metal. Therefore, when a dielectric breakdown occurs between a pair of opposing electrodes, a function to prevent the divided electrodes involved in the dielectric breakdown part from being electrically disconnected from the capacitor body and released, and causing dielectric breakdown of other microcapacitor groups. Have (hereinafter referred to as the security mechanism).

Among the safety devices, the one having the structure shown in FIG. 3 has a mechanical weak point part surrounded by an insulating tube 9 between the external terminal 6 attached to the upper lid 5 and the capacitor element 8 attached in the outer container 7. The lead wire 11 provided with 10a is connected, and the mechanical weak point 10
This is a device for separating the external terminal 6 and the capacitor element 8 by opening a (hereinafter simply referred to as bellows type safety device).

Further, in the one shown in FIG. 4, the external terminal 6 attached to the upper lid 5 and the lead wire 11 drawn out from the capacitor element 8 attached in the outer container 7 are connected to each other to form a mechanical weak point portion of the outer container 7. A device for disconnecting the external terminal 6 and the lead wire 11 at the mechanical weak point portion 10b by causing the upper lid 5 to be bulged outward by increasing the internal pressure (hereinafter simply referred to as a cut-off type safety device), and It has the function of interrupting the supply of electrical energy to the capacitor due to an increase in the internal pressure of the outer container, even if there is abnormal heat generation due to dielectric breakdown or overcurrent flowing to the capacitor.

However, in a capacitor with a safety mechanism, when the ambient temperature rises, the space between the film layers becomes narrower due to heat and the corona starting voltage becomes higher. Then, a large dielectric breakdown does not occur before the high temperature breakdown, and a small breakdown current that does not reach the minimum fusing current flows at the time of the high temperature breakdown, so that the safety mechanism does not operate. When the safety mechanism stops operating due to heat destruction, the capacitor runs out of heat and eventually destroys with smoke and ignition.

Regarding the breakdown at the portion functioning as a dielectric, the safety mechanism operates because each divided electrode has a fuse, but abnormal contact between the end surface of the insulating film 1 and the sprayed metal or abnormal lead wire in the capacitor container. Not protected against. Therefore, heat is likely to be generated from that portion, and once heat is generated, the capacitor is thermally runaway and eventually breaks with smoke or ignition.

On the other hand, in the case of a capacitor with a safety device, the dielectric breakdown of only one place where the capacitor element is present develops into the dielectric breakdown of all the capacitor elements, and the gas generated at that time causes the safety device to operate to function as the capacitor. I will lose. In other words, there is no tendency for the rest of the capacitors to continue functioning, with only partial destruction like the safety mechanism. Moreover, the gas generation speed varies considerably depending on the individual dielectric material, applied voltage, and temperature. In the case of a high-voltage capacitor, the gas generation speed at the time of dielectric breakdown is very fast, so an external terminal was connected. The lid of the outer container blows off with the force of gas from the outer container, which is low in safety. In particular, when an element in which the capacitor element is covered with a resin is used as a capacitor with a safety device, the gas until the resin breaks through spreads all the way into the capacitor container, so that the lid of the capacitor tends to almost come off.

When the outer container is defective due to rust or the like when used for a long period of time, the outer container cannot be hermetically sealed, so that the safety device does not operate and the capacitor heats up to cause thermal runaway. May be destroyed by smoke or fire.

[0009]

As described above, the conventional problem is that, in the safety mechanism, if the thermal destruction element is large, it will not operate, or heat will be easily generated in the metal sprayed portion. Further, in the security device, the life of the capacitor is shortened, or the security device itself does not operate due to a defect in the outer container.

Therefore, the present invention is intended to solve the problems of the above-mentioned conventional safety mechanism and safety device, and to prevent damage due to overvoltage or thermal runaway when a capacitor is used under severe conditions. In this case, it is an object of the present invention to realize a capacitor with high safety and reliability that ensures the safety function to operate and has a long life.

[0011]

In order to achieve the above object, the capacitor of the present invention is an outer container provided with a safety device, which is a capacitor element made of a metallized film which is a safety mechanism by dividing a metal vapor deposition electrode. The inside of the capacitor element or the entire capacitor element covered with a thermosetting resin,
Further, it is configured to be loaded into an outer container provided with a security device.

[0012]

With this structure, even if the safety mechanism does not operate against thermal destruction due to high ambient temperature or if destruction occurs due to heat generation in the metal sprayed portion, an outer container provided with a safety device is provided. Since it is loaded inside, the supply of electric energy to the capacitor can be cut off due to an increase in the internal pressure of the outer container due to thermal destruction, and the capacitor will not be destroyed by smoking or ignition.

Further, since the capacitor element is composed of a metallized film having a safety mechanism by dividing the metal vapor deposition electrode, only the reduction of the capacitance due to the dielectric breakdown of the split capacitor having the split electrode causes the entire capacitor to be heated. It can prolong the service life of the capacitor without destroying it, and even if the outer container becomes defective when it is used for a long time and the outer container cannot be kept sealed, the metal evaporated film is divided to provide a safety mechanism. It is safe because If the entire capacitor element is covered with a thermosetting resin, the capacitor element will not be exposed to danger.

Further, since the metal vapor deposition electrode is a capacitor element having a safety mechanism by dividing it, the divided electrodes involved in the dielectric breakdown portion are electrically disconnected from the capacitor body to cause dielectric breakdown, so that gas is generated at the time of breakdown. Since the speed becomes slower and the internal pressure of the outer container can be prevented from increasing rapidly, the lid of the outer container can be prevented from protruding from the outer container, and the capacitor can be destroyed by smoking or ignition. There is no. Hereinafter, a specific description will be given.

(Embodiment 1) When a double-sided vapor-deposited film of polyethylene terephthalate (hereinafter abbreviated as PET) film is obtained, a vapor-deposited electrode (split electrode) of aluminum having a pattern shown in FIG. The mechanism. A polypropylene (hereinafter abbreviated as PP) film was used as a laminated film, and the above two films were superposed and wound, and both surfaces of the capacitor element were subjected to metal spraying, followed by heat aging and lead wire attachment.

Then, the capacitor element made of the metallized film described above is loaded into an outer container provided with a bellows type safety device shown in FIG. 3 and impregnated with polybutene oil (hereinafter abbreviated as PO) to obtain an A capacitor. And

The manufactured capacitor has a rating of 200.
It is a capacitor having a capacitance of 60 μF at V.

For comparison of the embodiments, a capacitor with a security mechanism (capacitor element housed in a resin case and filled with epoxy resin) having a security mechanism similar to that of the embodiment of the present invention is used as a B capacitor. Also, a comparative capacitor, which is not provided with a safety mechanism and is mounted in an outer container provided with a bellows type safety device similar to that of the embodiment of the present invention, is simultaneously manufactured as a C capacitor.

(Embodiment 2) The capacitor element made of the metallized film obtained in the first embodiment is loaded into an outer container provided with the interruption type safety device shown in FIG. 4 and impregnated with PO. A capacitor was used.

The manufactured capacitor has a rating of 200.
It is a capacitor having a capacitance of 60 μF at V.

A comparative capacitor, which has no safety mechanism for comparison with the present embodiment but is mounted in an outer container provided with a shut-off type safety device similar to that of the present invention, was simultaneously manufactured as a C capacitor.

(Embodiment 3) The entire capacitor element made of the metallized film obtained in the first embodiment is covered with an epoxy resin, loaded into an outer container provided with a bellows type safety device, and PO is used. It was impregnated into an A capacitor.

The manufactured capacitor has a rating of 200.
It is a capacitor having a capacitance of 60 μF at V.

For comparison with this embodiment, a capacitor with a security mechanism having the same security mechanism as that of this embodiment (a capacitor in which a capacitor element is mounted in a resin case and filled with epoxy resin) is used as a B capacitor. Further, a comparative capacitor, which is not provided with a safety mechanism but is mounted in an outer container provided with a bellows type safety device similar to that of the present embodiment, was simultaneously manufactured as a C capacitor.

(Embodiment 4) The whole capacitor element made of the metallized film obtained in the first embodiment is covered with an epoxy resin, loaded into an outer container provided with a shut-off type safety device, and PO is used. It was impregnated into an A capacitor.

The manufactured capacitor has a rating of 200.
It is a capacitor having a capacitance of 60 μF at V.

A comparative capacitor, which has no safety mechanism for comparison with this embodiment, but is installed in an outer container provided with a shutoff type safety device similar to that of this embodiment, was simultaneously manufactured as a C capacitor.

(Embodiment 5) A PP film is prepared as a laminated film with a double-sided vapor-deposited film of the PET film obtained in the first embodiment, two films are laminated to form a ring, and metal spraying is performed on both surfaces. After applying and heat aging, cutting and lead wire attachment were performed.

Then, the capacitor element made of the above metallized film was loaded into an outer container provided with a bellows type safety device and impregnated with PO to obtain an A capacitor.

The manufactured capacitor has a rating of 200.
It is a capacitor having a capacitance of 60 μF at V.

For comparison with this embodiment, a capacitor with a security mechanism having the same security mechanism as that of this embodiment (capacitor in which resin element is mounted in resin case and filled with epoxy resin) is used as B capacitor. Also, a comparative capacitor, which has no security mechanism but is mounted in an outer container provided with a security device similar to that of the embodiment, was simultaneously manufactured as a C capacitor.

(Embodiment 6) The capacitor element made of the metallized film obtained in the fifth embodiment is loaded into an outer container provided with a blocking type safety device and impregnated with PO to obtain A.
It was a capacitor.

The manufactured capacitor has a rating of 200.
It is a capacitor having a capacitance of 60 μF at V.

For comparison with the embodiment of the present invention, a comparative capacitor, which has no safety mechanism but is provided with an interruption type safety device similar to that of the embodiment of the present invention, was simultaneously manufactured as a C capacitor.

(Embodiment 7) The whole capacitor element made of the metallized film obtained in the fifth embodiment is covered with an epoxy resin and loaded in an outer container provided with a bellows type safety device, and PO is used. It was impregnated into an A capacitor.

The manufactured capacitor has a rating of 200.
It is a capacitor having a capacitance of 60 μF at V.

For comparison with this embodiment, a capacitor with a security mechanism having the same security mechanism as that of this embodiment (capacitor in which resin element is filled with epoxy resin) is used as B capacitor. Further, a comparative capacitor, which is not provided with a safety mechanism but is mounted in an outer container provided with a bellows type safety device similar to that of the present embodiment, was simultaneously manufactured as a C capacitor.

(Embodiment 8) The whole capacitor element made of the metallized film obtained in the fifth embodiment is covered with an epoxy resin and loaded in an outer container provided with a shut-off type safety device, and PO is used. It was impregnated into an A capacitor.

The manufactured capacitor has a rating of 200.
It is a capacitor having a capacitance of 60 μF at V.

Then, for comparison with this embodiment, a comparison capacitor loaded in an outer container provided with a shut-off type safety device similar to this embodiment was simultaneously manufactured as a C capacitor.

The capacitors manufactured in the first embodiment are forcibly destroyed by conducting a voltage boosting test in an atmosphere of maximum allowable temperature + 30 ° C., and the results are shown in FIG. If there is a defect in
A safety function operation test at high temperature was also conducted at the same time, and the results are shown in (Table 1).

[0042]

[Table 1] From FIG. 1, the B capacitor with the safety mechanism has a large thermal destruction factor, so that the safety mechanism does not operate, and all of them are destroyed with smoke. Further, in the C capacitor with a safety device (bellows type and interruption type) and the A mechanism with a safety mechanism and a safety device (bellows type and interruption type) of the present embodiment, 100% of the safety devices operate, and smoke and ignition are involved. Although the destruction did not occur, the remaining rate of the capacitor is A with the safety mechanism and the safety device of the present embodiment (bellows type and cutoff type).
Capacitors were more expensive than C-capacitors with no safety mechanism and only safety devices (bellows and cutoffs). This is because in the case of a C capacitor with a safety device (bellows type and cutoff type), the insulation breakdown occurs between the opposing electrodes at a certain point, and heat is generated from that part, which increases the internal pressure of the outer container. This is because the device operates and the supply of electric energy to the capacitor is cut off, and the function as the capacitor is lost.

Further, from (Table 1), at room temperature, a B capacitor having only a safety mechanism, a C capacitor having only a safety device (bellows type and a cutoff type), and a safety mechanism and a safety device of the embodiment are included. Both (bellows type and cutoff type) A capacitors operate the total safety function, but at high temperature the thermal destruction element becomes large, so the B capacitor with only the safety mechanism will not operate the safety mechanism.
It can be seen that 7 out of 10 units were destroyed due to smoking. Further, it can be seen that if a defect occurs in the outer container, all of the C capacitors having only the safety device (bellows type and blocking type) do not operate and are destroyed with smoke. On the other hand, the safety mechanism and the safety device of the present embodiment (bellows type and shutoff type) A
It can be seen that the capacitors did not break with smoke or fire, even if the capacitors were operated at high temperature or if the outer container had a defect.

Further, in this embodiment, since the metal vapor deposition electrode 2 is the capacitor element 8 having a safety mechanism by dividing it, the divided electrodes involved in the dielectric breakdown portion are electrically disconnected from the capacitor main body to cause dielectric breakdown, Since the gas generation speed at the time of destruction becomes slower and the sudden increase in the internal pressure of the external container can be suppressed, the upper lid 5 of the external container 7 is prevented from escaping from the external container 7, and the capacitor emits smoke or fire. It has an extraordinary effect that it will not be destroyed with.

From the above results, the overcapacity of the A capacitor having both the safety mechanism and the safety device of the present invention is higher than that of the conventional B capacitor having only the safety mechanism and the C capacitor having only the safety device. It can be seen that the capacitor has high safety and reliability, and has a long service life, in which the safety function reliably operates regardless of damage due to thermal runaway.

In this embodiment, the PP film is used as the laminated film for the PET vapor deposition film, but the present invention is not limited to this structure. PP is used for the vapor deposition film and PET, PP for the derivative. Besides, polycarbonate, polystyrene, polyethylene, paper and the like can be used alone or in combination. You may form a capacitor by laminating two single-sided vapor deposition films of PP.
Also, zinc is used as the metal to be deposited on the film in addition to aluminum, and urethane resin is used in addition to epoxy resin to cure the metallized film capacitor element. The same effect can be obtained by using an oval for sealing the outer container with air in addition to impregnating it with PO.

[0047]

As described above, according to the present invention, a capacitor element made of a metallized film having a metallized film as a safety mechanism by dividing a metal vapor-deposited electrode, or the above capacitor element entirely covered with a thermosetting resin, By loading the capacitor in an outer container provided with a safety device, a highly safe and highly reliable capacitor having a reliable safety function and a long life can be realized.

[Brief description of drawings]

FIG. 1 is a diagram showing a voltage boosting test result of an A capacitor, a comparative B capacitor, and a comparative C capacitor according to an embodiment of the present invention.

FIG. 2 is a front view of a part of a vapor deposition film.

FIG. 3 is a half cross-sectional view of a bellows-type capacitor with a safety device.

FIG. 4 is a half cross-sectional view of a capacitor with a cutoff protection device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Insulation film 2 Metal vapor deposition electrode 3 Metallized film 4 Fuse part 5 Upper lid 6 External terminal 7 Exterior container 8 Capacitor element 9 Insulation tube 10a, 10b Mechanical weak point 11 Lead wire

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Eiichi Wada 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (11)

[Claims] 1. A capacitor comprising a capacitor element having a metallized film as a safety mechanism formed by dividing a metal vapor deposition electrode into an exterior container provided with a safety device. 2. A capacitor element having a metallized film having a safety mechanism formed by dividing a metal vapor deposition electrode and covering the whole with a thermosetting resin is loaded in an outer container provided with a safety device. And the capacitor. 3. The metallized film is a polyethylene terephthalate film in which aluminum is vapor-deposited on both sides, and at least one metal vapor-deposited electrode facing each other is divided into a plurality of pieces. Capacitor described in. 4. The capacitor according to claim 1, wherein the metallized film is a polypropylene film having aluminum vapor-deposited on one surface, and at least one metal vapor deposition electrode is divided into a plurality of parts. 5. The capacitor according to claim 1, wherein the metallized film is a polypropylene film having zinc deposited on one side thereof, and at least one metal deposition electrode is divided into a plurality of parts. 6. The capacitor according to claim 1, wherein the capacitor element having the metallized film is a round type or an oval type. 7. The capacitor according to claim 2, wherein an epoxy resin or a urethane resin is used as the thermosetting resin. 8. The outer container is connected with a lead wire having a mechanical weak point between an external terminal attached to the upper lid and a capacitor element installed in the outer container, and the mechanical weak point is increased due to an increase in internal pressure of the outer container. The capacitor according to claim 1 or 2, further comprising a safety device that disconnects the external terminal and the capacitor element by opening the portion to cut off the supply of electric energy to the capacitor. 9. The outer container is provided with a mechanical weak point between an external terminal attached to the upper lid and a lead wire drawn from a capacitor element mounted in the outer lid, and the upper lid is moved outward due to an increase in the inner pressure of the outer container. The capacitor according to claim 1 or 2, further comprising a safety device that disconnects the external terminal and the lead wire at the mechanical weak point by inverting and projecting, and interrupts the supply of electric energy to the capacitor. 10. The capacitor according to claim 1, wherein the capacitor element having the metallized film is filled with polybutene when the capacitor element is loaded into an outer container provided with a safety device. 11. The capacitor according to claim 1, wherein the capacitor element having the metallized film is hermetically sealed together with air in the atmosphere when the capacitor element is loaded into an outer container provided with a safety device.